Heart pump device and method for operating same

ABSTRACT

A heart pump device may be provided with an implantable heart pump, which has at least one sensor, wherein at least one of the sensors is a sensor for a rotor of the heart pump, and with a control device, which is connected to the heart pump by means of a transcutaneous line, characterised by a signal processing device, which on the one hand is connected by means of the transcutaneous line to the control device, and which on the other hand is connected to at least one sensor of the heart pump and transmits signals of at least one sensor via the transcutaneous line to the control unit. The signal processing device may be for a pre-processing of the sensor data for more efficient transmission via the transcutaneous line.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. non-provisional applicationSer. No. 15/558,961, filed Sep. 15, 2017, which is a 371 nationalizationof international patent application PCT/EP2016/055810 filed date of Mar.17, 2016, the entire contents of which are hereby incorporated byreference, which in turn claims priority under 35 USC § 119 to Europeanpatent application EP 15159496.7 filed on Mar. 17, 2015.

TECHNICAL FIELD

The invention lies in the field of electrical engineering and especiallymedical engineering and can be used specifically in conjunction withheart pumps.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a section through a heart wall with an implanted heart pumpof a first design;

FIG. 2 shows a section through a heart wall with an implanted heart pumpof a second design;

FIG. 3 shows a three-dimensional external view of a heart pump with asubstantially polygonal annular printed circuit board surrounding aninlet connection piece of the pump;

FIG. 4 shows a view of a base of a heart pump, in which a signalprocessing device is integrated;

FIG. 5 shows the combining of the sensor data from different sensors ina signal processing device which is connected by means of a signal busto a control device; and

FIG. 6 shows a signal processing device which forwards the signal of aposition sensor, at least in the event of a fault, with bypassing of keyparts of the signal processing device via the transcutaneous line.

DETAILED DESCRIPTION

For some time, implantable electric heart pumps for assisting the humanheart have been known, which for example can be designed as an LVAD(left ventricular assist device), RVAD (right ventricular assist device)or BiVAD (bi-ventricular assist device) and in this case convey bloodfrom the left heart ventricle into the aorta. Pumps of this type areusually supplied with power and controlled from outside the body. Tothis end, one or more wired lines is/are usually provided, which supplyelectrical power to, and control, the actual heart pump, in particular amotor provided in the heart pump. In addition, data is detected withinthe implanted heart pump via sensors, such as the rotor position of theheart pump, the pump temperature, the ventricle blood pressure, theblood temperature, position information, angular accelerations, acousticsignals, intrathoracic pressure, and similar variables, and this data isreceived and processed, in particular also stored, by a control devicedisposed outside the patient's body.

A number of lines or cores of lines are usually provided for connectionof the sensors and of the pump motor to the control device so as totransport all data and the energy in the form of an individual wiringthrough a combined transcutaneous or percutaneous cable. Due to thelarge number of cores, the cross-section of the transcutaneous lines orof the cable is relatively large, so that the primary piercing pointposes an increased infection risk. In addition, a combined line of thistype is rigid due to the large cross-section and is likely to break. Thenumber of sensors is hereby limited, since the diameter of the combinedline increases further due to further lines that need to be added.

Solutions are also known in which a transmission of data takes place viaa radio link from inside the body to outside the body, however acommunication connection of this type has certain failure risks, so thata wired connection is desirable as safeguard. By way of example, acontinuously determined rotor position of the drive of the heart pumpcan be important for the drive control.

Against the background of the prior art, the object of the presentinvention is therefore to connect a control device—arranged outside thebody—for a heart pump device to a heart pump with minimal effort andminimised risk of infection.

The invention thus relates to a heart pump device with an implantableheart pump that has at least one sensor, wherein at least one of thesensors is one of the following sensors: a position sensor for a rotorof the heart pump; a position and/or acceleration sensor; a volume flowrate sensor; a temperature sensor; a pressure sensor; a pressuredifference sensor; an oxygen saturation sensor; a chemical sensor forblood analysis. The heart pump device also comprises a control devicethat is connected to the heart pump by means of a transcutaneous orpercutaneous line. By way of example, a transcutaneous line isunderstood to mean a line that is guided through the skin. By contrast,a percutaneous line by way of example runs entirely in the body and isoften guided at least to a point in the vicinity of the skin surface andfor example is coupled to a TET (transcutaneous energy transfer) system.Here, the TET system is configured in such a way that, besides energy,preferably digital data can also be exchanged.

The invention also relates to a signal processing device, which on theone hand is connected by means of the transcutaneous or percutaneousline to the control device and which on the other hand is connected toat least one sensor of the heart pump and in a first operating statetransmits signals of the at least one sensor to the control unit. Here,the signals are transmitted in some embodiments via the transcutaneousor percutaneous line.

The signal processing device, similarly to the heart pump, isimplantable and is directly connected to one or more sensors of theheart pump and provides a pre-processing of the signals from one or moresensors in such a way that these signals by way of example can betransmitted in a simplified manner via the transcutaneous orpercutaneous line. Here, signals from different sensors can also becombined or connected, for example by combining a number of signals viaa bus system. In particular, the signal processing device in a firstoperating state of the heart pump device can combine a multiplicity ofsignals to be transmitted—or in some exemplary embodiments all signalsto be transmitted—from sensors and can transmit these via atranscutaneous or percutaneous line embodied as a databus. Thetranscutaneous line for this purpose can have one or more cores ofelectrical conductors and can serve as a line for a serial or parallelbus. Transmission via an optical signal line by the signal processingdevice is also possible. In addition, a combination of theenergy-transmitting lines with the data-transmitting lines is possible(power-line communication).

In order to set up a databus system, fewer lines are usually requiredthan in the case of an individual wiring of the sensors and individualconnection of the sensors to the control device arranged outside thepatient's body.

In addition, the signal processing device can store data of theindividual sensors and for example can also store data suitable for acalibration of the signals. This has the advantage that the data can beinterpreted in the control device independently of the furthercommunication path over which it must travel between the signalprocessing device and the control device. The information arriving atthe control device is not dependent on the individual pairing between aheart pump and a control device. In the event of a replacement of thecontrol device, there is thus no need for any calibration orinitialisation with a specific heart pump. This leads to significantsimplifications with regard to the storage and installation of controldevices. There is also no need to set up and use a heart pump andcontrol device as a fixed pair in each individual case.

The signal processing device is connected in some exemplary embodimentsat least to one of the aforementioned sensors. In one embodiment, atleast one of the sensors is a position sensor of a rotor of the heartpump. In this case, the position sensor is for example a sensor thatgives the position of the rotating rotor of an electric motor in theheart pump. The transmission of position data of this type is importantfor the control in particular of brushless electric motors, which areused advantageously in the field of medical engineering, since they areextremely efficient, can be easily controlled, and are low-maintenance.

A sensor that determines the angular position of the rotor bycalculating current and voltage of a brushless electric motor via therotor retroactivity can also serve as sensor for the position of therotor of the heart pump.

The signal processing device can additionally also be connected tofurther sensors, for example two, three, four or more sensors, whereinthese sensors can be provided in or on the heart pump and for exampleare formed as one of the aforementioned sensors or as pump temperaturesensor, blood pressure sensor or blood temperature sensor. The signalprocessing device and the implantable heart pump can undergo an initialset-up together with the used sensors at the time of initial operationor at the factory prior to initial operation, wherein calibration occursvia known reference values and corresponding calibration parameters canbe stored in the signal processing device. The heart pump can thuscooperate, jointly with the signal processing device, with any externalcontrol device without further calibration. The external control devicetherefore can be replaced without difficulty and can be used withoutfurther initial set-up.

The signal processing device is advantageously arranged directly on theheart pump. This allows a problem-free joint implantation of heart pumpand signal processing device and additionally short signal paths betweenthe sensors of the heart pump and the signal processing device. Thesignal processing device can also be held mechanically on the heartpump, for example can be mounted thereon, so that hereby the relativeposition of heart pump and signal processing device is clearly defined.

A further advantageous embodiment of the invention provides that atransmitting device is provided in the immediate vicinity of the heartpump, in particular is directly connected thereto, and processes thesignals of at least one sensor and transmits these by means of awireless connection. For the normal situation of fault-free operation,the data detected by the sensors can be transmitted via radio withoutuse of the transcutaneous line. However, it is conceivable to use bothtransmission paths in parallel and to compare the transmitted signals inthe control device so as to achieve a higher reliability. At least inthe case in which the transmitting device fails, a switch is madeimmediately to the signal processing device and transmission via thetranscutaneous line. In addition, the transcutaneous or percutaneousline is required permanently for the transmission of electrical energyin the form of a feed voltage for a motor of the heart pump.

A further advantageous embodiment of the invention provides that aswitching module is provided within the signal processing device, whichswitching module causes a second operating state to be implemented inthe event of a fault of the signal processing device, in which secondoperating state the signal of the position sensor (or of the particularsensor used) is transmitted directly via the transcutaneous orpercutaneous line, with bypassing of key parts of the signal processingdevice.

If, by way of example, a position sensor is used for a rotor of a heartpump and the data detected by means of this position sensor is processedin the first operating state of the heart pump device by means of thesignal processing device and is transmitted via the transcutaneous orpercutaneous line, the signals in the second operating state aresubstantially not processed by the signal processing device, but insteadare fed directly into the transcutaneous or percutaneous line. Since acontinuous and reliable transmission of the axial position of the rotorand/or the angular position of the motor of the heart pump can be veryimportant for the operation and the control of the motor depending onthe pump type used, these variables of the corresponding sensor have tobe transmitted with increased certainty. For this reason, the signalprocessing device can have a self-monitoring device, for example what isknown as a watchdog, which detects malfunctions and in the event of amalfunction, by means of the switching module, bypasses the signal pathconnecting the corresponding sensor, in particular the position sensor,to the signal processing device and further to the control device, insuch a way that the signal of the sensor is guided past key parts of thesignal processing device and is guided directly via the transcutaneousor percutaneous line to the control device.

It can also be provided that further sensors are qualified in such a waythat in the case of a malfunction of the signal processing device thesignals delivered thereby are conducted directly by a switching moduleand are conducted past key parts of the signal processing device, viathe transcutaneous or percutaneous line to the control device. However,in this case, since the transcutaneous line manages with minimal cores,the transmission of all sensor signals directly via the transcutaneousline is not necessarily possible. However, the transmission of the mostimportant signals via the transcutaneous or percutaneous line in thesecond operating state is also secure if the signal processing devicefails, for example.

For an advantageous embodiment of the invention, it can additionally beprovided for example that the signal processing device has at least onememory device for storing system parameters, in particular parameters ofthe heart pump, and/or measured values of one or more sensors. A memorydevice of this type allows the calibration of the pairing of heart pumpand signal processing device and also the storage of critical sensordata, wherein alarm signals for example are to be output when saidcritical sensor data occur or are overshot.

The signal processing device advantageously has a microcontroller and/ora transceiver, for example an RS485 transceiver. The heart pump deviceis thus equipped for efficient data transmission by means ofcommunication standards which are only susceptible to faults to aminimal extent.

A further advantageous embodiment of the invention provides that thesignal processing device has at least one flexible, in particularbendable or foldable printed circuit board. The signal processing deviceis usually constructed as an electric circuit with individual circuitelements and/or integrated circuits, for example also ASICs. On accountof the small amount of space available, flexible or foldable printedcircuit boards which can be adapted accordingly to the amount of spaceavailable are suitable for the construction.

In this regard, it can be provided particularly advantageously that thesignal processing device is arranged annularly around an inflow oroutflow channel of the heart pump. In the form of a bendable printedcircuit board, the signal processing device can form an annular polygon,which surrounds an inflow or outflow line of the pump.

It can also be provided that the signal processing device is arranged ona flat housing base of the heart pump. A printed circuit board of thesignal processing device can thus form a housing base of the pump or canrun parallel to a housing base of the pump.

Apart from a heart pump device, the present invention also relates to amethod for operating a heart pump device in one of the above-describedembodiments, in which the heart pump together with its signal processingdevice is connected to a control device, and in which pump parametersare detected and are stored in the signal processing device. As aresult, the pump is set up initially with the signal processing deviceand is calibrated as appropriate, and therefore the heart pump workstogether with any control device without the need for a furtheradaptation. The necessary calibration parameters are stored in thememory device of the signal processing device and can be called uptherefrom.

During operation, the signal processing device forwards pre-processedsignals from sensors via a databus by means of the transcutaneous orpercutaneous line.

The invention will be presented hereinafter with reference to anexemplary embodiment in figures of a drawing and will be describedhereinafter.

FIG. 1 shows an implantable heart pump 1, the inlet connection piece 2of which is embedded in a heart wall 3 in the region of the leftventricle, in such a way that the pump 1 can convey blood from the heartchamber 4 into an artery (not illustrated). The direction of flow of theblood is indicated by the arrows 5, 6. The heart pump 1 has a rotor 7,which on the 1 hand has electromagnetic drive elements, such as anarmature, and on the other hand conveying elements 8 in the form ofblades, which for example convey blood in the axial direction 9 to thepump outlet 10. Sensors for various physiological variables, such asblood temperature and ventricle pressure, are usually arranged in theregion of the heart pump 1, and also sensors for measuring thetemperature of elements of the pump, a sensor for the accelerationmeasurement, which gives information with regard to a movement of thepatient, and a sensor that detects the angular position of the rotor ofthe pump.

The rotary position sensor is necessary in particular with use of amagnetic bearing in order to determine the axial rotor position. Thisforms an important input variable for the control of the bearing andthus the magnetic mounting of the rotor. This is the case for example inINCOR pumps from Berlin Heart GmbH.

FIG. 2 shows a heart pump 1′, of which the inlet connection piece 2′ isalso embedded in the heart wall 3 in the region of the left ventricle 4,wherein the axis of rotation 9′ of the rotor 7′ runs in the longitudinaldirection of the inlet connection piece 2′. Here, the drive part 11 ofthe rotor with the armature and, as applicable, also a winding arehoused in the inlet connection piece 2′, whereas the rotor part with theconveying elements 12 is arranged in the pump housing 13. The rotor 12accelerates the blood in the radial direction and partly in thetangential direction, so that it leaves the pump through the outletconnection piece 10′. A brushless electric motor can be used in thisembodiment of the heart pump as well.

FIG. 3 shows an external view of a heart pump 1′ with an inletconnection piece 2′ and an outlet connection piece 10′ and a pumphousing 13 in approximately cylindrical design, wherein a printedcircuit board 14 folded in a polygonal manner is illustrated around theinlet connection piece 2′ and carries electrical component parts of asignal processing device, although these are not illustrated in detail.FIG. 3 shows merely a space-saving arrangement of the signal processingdevice around the inlet connection piece 2′ between the pump housing 13and the heart wall 3. The printed circuit board 14 can have for examplefilm hinge connections at the bending points 15, 16 between individualflat, planar printed circuit board parts, wherein conductor tracks ofthe printed circuit board can pass over the bending lines 15, 16.

FIG. 4 shows a view of a pump housing 13 as considered from the base ofthe pump, wherein an insert part 17 is installed in the base and cancarry electrical components of a signal processing device. In this wayas well, a signal processing device can be arranged on the heart pump 1′in a space-saving and directly protected manner.

FIG. 5 shows in detail on the left side five sensors, specifically anelectronic temperature sensor 18, an acceleration sensor 19, a bloodtemperature sensor 20, a ventricle pressure sensor 21, and a rotorposition sensor 22, each of which is connected to a microcontroller 23.The microcontroller 23, together with a bus interface 24, forms a signalprocessing device 34, which communicates bidirectionally with a controldevice 26 via the transcutaneous or percutaneous line 25. Here, sensormeasured values from the sensors 18, 19, 20, 21, 22 are transmitted viathe transcutaneous bus line 25 to the control device 26, and signals canbe conducted from the control device 26 to the heart pump, for examplethe drive of the heart pump. These include, for example, electricalsignals for controlling the magnetic bearing. The transcutaneous line 25can additionally be used for signal transmission and for thetransmission of electrical energy.

The microcontroller 23 can combine the signals of the sensors or aselection of the sensors and can process these in such a way that theycan be sent by means of a common communication protocol to the controldevice 26. As a result, the necessary line capacity of thetranscutaneous line 25, for example the number of the required cores,can be reduced to a minimum, so that the transcutaneous line is thin andflexible and is thus less likely to break and in addition has a smallouter surface and therefore offers a smaller interface to the tissue ofthe patient's body as potential attack area for infections.

The tissue layer through which the transcutaneous line 25 runs tooutside the body, where the control device 26 is also arranged, isindicated by the two dashed lines 27, 28. In the case of a percutaneousline, this would lead for example to a TET interface arranged in thebody, which can be coupled to a corresponding TET interface arrangedoutside the body. A control device could be arranged in the body, forexample in the vicinity of the internally arranged TET interface and ata distance from the pump or pump electronics. Alternatively, the controldevice can also be arranged outside the body.

A radio link is provided parallel to the transcutaneous line 25, with animplanted transmitter 35, a transmitting antenna 36, a receiver 38, anda receiving antenna 37 outside the patient's body.

FIG. 6 shows that the microcontroller 23 can be bypassed by a bypassline 29 starting from the rotor position sensor 22. Whereas in the firstoperating state a multiplicity of sensor signals are processed by thesignal processing device, the signal processing device for exampledigitalises the sensor signals or aggregates various signals, in thesecond operating state—for example in the case of a fault—themultiplicity of sensor signals or in some exemplary embodiments merelysome of the sensor signals are transmitted via the bypass line 29, withbypassing of the microcontroller 23, to the control device arrangedoutside the body.

The sensor data from the sensors 18, 19, 20, 21, 22 is usually conductedto the microcontroller 23, processed there, and conducted from themicrocontroller 23 for example via a RS485 transceiver 24′ to thetranscutaneous line 25, and via this to the external control device 26.The signal of the rotor position sensor 22 or a signal reflecting theposition of the rotor can additionally be conducted by a low-passfilter, which is arranged upstream of the microcontroller.

In numerous exemplary embodiments, a monitoring device (for example awatchdog) is provided, which checks the correct functioning of themicrocontroller 23. If a fault of the microcontroller 23 is signalled,the monitoring device by way of example can actuate a switch 32, whichfor example is an analogue switch and which transfers the heart pumpdevice from a first operating state into a second operating state, inwhich the signal of the rotor position sensor 22, which reaches theswitch via the bypass line 29, is connected through to the transceiver24′. The signal of the rotor position sensor is thus conducted directlyand without passing through the microcontroller, i.e. bypassing keyparts of the signal processing device, to the transceiver 24′ and thecontrol device 26. It is thus ensured with a high level of certaintythat the signals, for example the signals of the rotor position sensor,reach the control device 26 even in the event of a malfunction of themicrocontroller, so that the drive of the heart pump can also becontrolled properly under consideration of the rotor position. Thecontrol device 26 is for this purpose, and for the purpose of energytransfer, connected either via an additional line (not illustrated) oralso via the transcutaneous line 25 to the motor drive of the heart pumpmotor.

In addition, a transcutaneous connection from outside the body to animplanted voltage supply 33 is also illustrated in FIG. 6. Thetranscutaneous connection, however, can alternatively also bepercutaneous. In the case of a percutaneous line, the above-mentionedconnection can also be percutaneous or transcutaneous.

As a result of the invention, the transcutaneous line 25 can thus beselected with minimal cores and a small surface, wherein at the sametime a high functional reliability of the heart pump and a reliablecontrollability are ensured.

1. A heart pump device comprising: a control device and an implantableheart pump, the heart pump including at least one sensor, the at leastone sensor including a pressure sensor and/or a pressure differencesensor, wherein the control device is connected to the heart pump by atranscutaneous or percutaneous line, wherein a signal processing deviceis arranged directly on the heart pump, wherein the signal processingdevice is connected by the transcutaneous or percutaneous line to thecontrol device, and the signal processing device is connected to the atleast one sensor of the heart pump, wherein the signal processing deviceis configured to pre-process and digitalize a plurality of sensorsignals of the at least one sensor and transmit the sensor signals tothe control device.
 2. The heart pump device according to claim 1,wherein the at least one sensor includes the pressure sensor, and thepressure sensor is provided at or near an inflow channel of the heartpump.
 3. The heart pump device according to claim 1, wherein the atleast one sensor includes the pressure sensor, and the pressure sensoris a micromechanical pressure sensor.
 4. The heart pump device accordingto claim 1, wherein the signal processing device is held mechanically inthe heart pump.
 5. The heart pump device according to claim 1, whereinthe at least one sensor of the heart pump device comprises at least twosensors connected to the signal processing device.
 6. The heart pumpdevice according to claim 5, wherein the at least two sensors includespressure sensors, and wherein the signal processing device is configuredto compute a mean of the respective sensor signals in a pre-processingof the sensor signals.
 7. The heart pump device according to claim 1,wherein the signal processing device is configured to store data for acalibration of the sensor signals, so that a calibrated and/ornormalized pressure signal is transmitted by the signal processingdevice.
 8. The heart pump device according to claim 1, wherein thesignal processing device includes at least one memory device for storingsystem parameters and/or measured values of the at least one sensor. 9.The heart pump device according to claim 1, wherein the signalprocessing device includes a transceiver for a digital buscommunication.
 10. The heart pump device according to claim 1, whereinthe signal processing device includes at least one flexible printedcircuit board arranged annularly around an inflow channel of the heartpump.
 11. The heart pump device according to claim 1, wherein atransmitting device is directly connected to the heart pump, and isconfigured to process the sensor signals of the at least one sensor andtransmit the sensor signals by means of a wireless connection.
 12. Theheart pump device according to claim 1, wherein the signal processingdevice includes a microcontroller.
 13. The heart pump device accordingto claim 1, wherein the transcutaneous or percutaneous line isconfigured to conduct a supply voltage.
 14. The heart pump deviceaccording to claim 1, wherein the signal processing device is arrangedannularly around an inflow or outflow channel of the heart pump.
 15. Theheart pump device according to claim 1, wherein the signal processingdevice is arranged on a flat housing base of the heart pump.
 16. Theheart pump device according to claim 1, wherein the signal processingdevice includes a switching module, wherein the signal processing deviceis configured to process, in a first operating state, the sensor signalsof the at least one sensor and is further configured to transmit thesensor signals to the control device, wherein the switching module isconfigured to transmit, in response to a fault of the signal processingdevice, the sensor signals of the at least one sensor in a secondoperating state directly via the transcutaneous or percutaneous line,with a bypassing of key parts of the signal processing device.
 17. Theheart pump device according to claim 1, wherein the signal processingdevice is configured to process the sensor signals from the at least onesensor and a databus is configured to transmit the sensor signalsaccording to a communication protocol.
 18. A method for operating aheart pump device, comprising a control device and an implantable heartpump, wherein the heart pump includes at least one sensor, the at leastone sensor including a pressure sensor and/or a pressure differencesensor, wherein the control device is connected to the heart pump,wherein a signal processing device is arranged directly on the heartpump, wherein the signal processing device is connected by thetranscutaneous or percutaneous line to the control device, and thesignal processing device is connected to the at least one sensor of theheart pump, wherein the signal processing device is configured topre-process and digitalize a plurality of sensor signals of the at leastone sensor and transmit the sensor signals to the control device, themethod comprising: connecting the heart pump, together with the signalprocessing device, to the control device; and detecting and storing pumpparameters in the signal processing device.
 19. The method according toclaim 18, further comprising processing signals from one or more sensorsby the signal processing device and forwarding, by a communicationprotocol, via a databus.